Typical areas of application of drivable or driven actuator positioning determining processes are employed, for example, by electromagnetically operated valves or switches. The inductance of the electromagnet depends on the particular position of the armature. Consequently, measurement of the inductance in essence permits determination of the position of the armature.
DE 33 26 605 A1 discloses a process and circuitry for monitoring the lifted position of the armature of a valve magnet. The winding is supplied with direct current having an alternating current-component. The alternating component depends on the position of the armature, and accordingly, the valve position, and is measured at a precision resistor by means of a high-pass filter.
The conventional process is disadvantageous in that the switching frequency being set also depends on the active resistance of the coil. The active resistance in turn depends to a relatively great extent on the temperature, which can create a disturbance variable in the output signal relating to the position of the armature. This disruptive effect is to be offset by circuit engineering measures on the basis of the direct-current component, as measured.